ARM Tachnology STM32 ST32
1 ARM Tachnology
Chapter 3 STM32 Clock and configuration Cortex Intelligent Processors by ARM
2 Chapter 3 STM32 Clock and Configuration
CONTENTS Objectives Clock System of STM32F103 Clock Configuration of STM32 sTM32 functions related to clock
3 CONTENTS • Objectives • Clock System of STM32F103 • Clock Configuration of STM32 • STM32 functions related to clock
3.1 Objectives All STM32 peripherals are driven by the clock, and every module uses independent clock to meet the low-power requirement. So STM32 clock system must be studied in detail to use peripherals properl
4 • 3.1 Objectives All STM32 peripherals are driven by the clock, and every module uses independent clock to meet the low-power requirement. So STM32 clock system must be studied in detail to use peripherals properly
3.2 STM32 Clock System There 5 clock sources in Stm32F103 HSI High Speed Internal) HSE(High Speed External LSI(Low Speed Internal) LSE(LOW Speed EXternal) PLL(Phase Locked Loop) Where, HIS, HSE, and pll can be used as system clock LSi and lse are second level clock The clock tree of stM32F103 is shown in Fig 11 on page 115 of the STM32 Reference Manual(RM)
5 3.2 STM32 Clock System There 5 clock sources in STM32F103： HSI (High Speed Internal) HSE (High Speed External) LSI (Low Speed Internal) LSE (Low Speed External) PLL(Phase Locked Loop) Where, HIS, HSE, and PLL can be used as System Clock. LSI and LSE are second level clock. The clock tree of STM32F103 is shown in Fig.11 on page 115 of the STM32 Reference Manual (RM)